Fluid pressure brake system for tractor-trailer vehicles



May 4, 1948 l. E. WIEGERS FLUID PRESSURE BRAKE SYSTEM FORTRACTOR-TRAILER VEHICLES Filed Nov. 3, 1944 2 Sh etS Shee-t 1 INVENTORVIN E. WIEGERS ATTORNEY- May 4 1948. 1. E. WIEGERS 3 4 FLUID PRESSUREBRAKE SYSTEM FOR TRACTOR-TRAILER VEHICLES Filed Nov. 5, 1944 2Sheets-Sheet 2 INVENTOR. I IN E WIEGERS ATTORNEY.

Patented May 4, 1948 fiTATEh canon @EFFHQE Film PRESSHJRE nnam SYQEEMFOR TRAQTQR-EWEE; VEMQLES Application November 3, 1M4}, Serial No.581,652

(ca. ite 3) 6 @iaims. i

This invention has reference to relay type pressure fluid control valvesand in its more specific aspects is directed to a relay valve forgoverning the application of the trailer brakes of a tractortrailercombination in the event of failure of the conduit connection betweenthe two units or the failure of the pressure fluid supply on thetractor, or an abnormally low pressure source of pressure fluid supply.

One of the objects of this invention is to provide a relay valve tocontrol the brakes of a tractor-trailer unit in the event of failure ofthe primary pressure fluid supply or a break in the conduit connectionsuch that the trailer brakes will be instantly applied in the event ofeither or both failures.

Another object of the invention is to provide a valve organization thatis responsive to pressure fluid failures in the tractor unit of thetractor-trailer combination.

A further object of the invention is the provision of a pressure fluidrelay valve that is more rapid and efficient in. its operation than anypresently known device.

Still another object of the invention is to provide an emergencyrelay'valve that provides an efficient means for controlling theapplication of reserve pressure fluid to the trailer brakes.

Another and still further object of the invention is to provide. anemergency relay valve in which the full reserve pressure fluid isapplied to the trailer brakes in the event of a failure of primarypressure fluid supply.

A still further object of the invention-is to provide-a better degree ofbalancing of pressure fluids in the several conduits and controlchambers of an emergency relay valve.

Other and further objects of the invention will occur to those skilledin the arts to which this application pertains as the descriptionproceeds, which, taken in connection with the accompanying drawings,sets forth a preferred embodiment of the invention but such disclosureis not to be construed as a. limitation of the invention which islimited only by the appended claims and any and all modifications,alterations and variations of structure coming within the spirit andscope thereof are deemed to be included herein.

In thedrawings:

Figure 1 is an elevational view of the improved emergency relay valvewith parts in section to show details;

Figure 2 is a view taken substantially along the line 2-2 of Figure 1;

Figure 3 shows a schematic brake and conduit assembly incorporating theimproved valve; and

Figure a is an enlarged view of a detail of Figure 2.

The achievement of the above objects and advantages is made possible inthe valve structure disclosed in the accompanying drawings in whichnumeral 1 indicates a housing provided with ports 2, 3, ti, and 5 towhich are connected the pressure fluid conduits of a brake controlsystem as hereinafter set forth in greater detail. Port d is providedwith a valve seat 6. Engageable with valve seat 6 is a normally closedcheck valve ll having a stem 3 with a spring 9 on the opposite side ofseat t, spring 9 being appropriately fixed with respect to the stern soas to urge the valve i to closed position.

Secured to the lower end of housing :1 is a cover plate it provided witha counterbored boss ll which is secured to the housing 9 by means of aplurality of screws H2, l2. Arranged in the largest of the counterboresin the cover plate it is the emergency valve diaphragm it which is of athickness suficient to be firmly clamped in position when screws i2, itare tightened. Co-

" axially disposed with respect to the next smaller of the counterboresin plate 5 t is a bore or charn= her it formed in housing l. Thediaphragm it, therefore, divides the two coaxial chambers in whichchamber it in housing 5 is closed and the chamber in cover 9 t is opento the atmosphere by way of vent it.

The housing 9 is provided with. bores it and fill each or which isappropriately shaped or contoured to receive suitable valve assemblies.The several valves control the flow of pressure fluid between theseveral bores in the housing, the emergency reserve supply, the primarysource of pressure fluid in the tractor-trailer combination and to thebrake operating motors.

The valve in bore H is a. compound valve. One part of the valvecomprises a movable seat 68 formed on stemi 9 secured to the emergencyvalve diaphragm I 3 by screw 2% with the flange on stem is placedagainst the diaphragm i3 and element 7 2| placed on the opposite side ofthe diaphragm,

said flange and element 2! reinforcing the diaphragm i3. Spring 22 isdisposed between element 2! and the bottom of counterbore i i in coverIn and urges the valve 25 to closed position.

Under certain conditions of operation, pressure fiuid is admitted tochamber M from the port 4 by means of duct or passageway 23 and urgesthe diaphragm i3 downward to withdraw seat l8 from its associatednormally closed valve 26. To prevent leakasc from-chamber to chamber 35around stem I8 and vice versa, seal 24 is provided Seal 25 also I whichacts to prevent such leakage. surrounding stem I8 acts to preventtransfer of pressure fluid around stem I8 or pressure fluid exchangebetween chambers 38 and 39.

The valve element 28 engageable with seat I8 is secured to a stem 21provided with a suitable valve receiving socket. The stem is received ina bushing 28 threaded into one of the internal collars in bore I1. Thestem 21 is grooved or'splined to permit the passage, of pressure fluidand is somewhat smaller in diameter than the bore in bushing 28.

Internally of the bushing and concentric with the bore therein is avalve seat 29 which is engageable with a normally open emergency valve38 secured to stem 21' by means of screw 3I which is the other part ofthe compound valve. Emergency valve 38 is urged downwardly by means of aspring 32, one end of which engages the emergency valve 38 and the otherend of which engages element 33 of the closure assembly secured to thehousing I by means of a plurality of screws 34, only one of which isshown, From the foregoing it is evident that bore I1-"is divided intothree chambers 31, 38, and 39, each of, which is connected to otherchambers in the valve or to ducts previously or to be subsequentlydiscussed.

As previously indicated, the element 33 of the closure assembly has acover plate 35 secured to the housing I and to the element 33 of theclosure assembly by a plurality of screws 38. The enlarged portion ofelement 33 has a double counterbore therein, the smaller bore of whichis concentric with a bore or cavity in the cover element 35 and is alsoconcentric with a bore formed in the housing I which may be considered apart of bore l8. Disposed in the largest of the counterbores in theenlarged portion of the element 33 is a pilot diaphragm 44 which isfirmly clamped in position by the cover plate 35 when the screws 38 aretightened. The other counterbore in the enlarged portion of 33 has therelay valve diaphragm 45 arranged therein which is clamped in positionagainst housing I when the aforementioned screws 35 are tightened. Thearrangement of the diaphragms 44 and 45 in the respective counterbores'divides the previously described concentric bores in housing I, theenlarged portion of closure member 33 and the cover plate 35 into threechambers designated as 48, 4I, and 42, respectively, all as more clearlyshown in Figure 2 of the drawings. A duct 41 formed in the enlargedportion of 33 connects the chamber 48 with the atmosphere and duct 43.connects chamber 38 with the chamber or cavity 4I.

The bore i6 has arranged therein a compound valve structure whichoriginates in a cage 48 held in the upper portion of bore I8 in twocollar-like projections formed therein and slidably disposed in saidbore. The upper end of the cage, as illustrated, is bored and threadedin order to receive a. head portion 48 having bores 58 therein whichconnect with the bore formed in the cage 48 and thence forms apassageway from the interior of the cage and the bore I8 to theatmosphere. The upper end of cage 48 has formed therein a valveseat I'cooperating with the normally open exhaust valve 52 arranged in a valveseat holder threadedly secured by means of a studto the valve stem 53.The stem 53 is concentrically disposed within the opening or space 49formed in cage 48.

In order to have a passageway between the oft-he bore I6 formed by thespace between the collars in the said bore in which the cage 48 restsand is slidably disposed, the cage 48 is formed with a plurality ofapertures 54 in order to provide such a passageway for the exhaustion ofany pressure fluid therefrom to the atmosphere when the normally closedexhaust valve 52 is in proper or open position.

On the lower end of stem 53 is an inlet valve 55 arranged in a holder 58threaded to the lower end of stem 53 and a spring 51 engages with theholder 56 to urge the entire assembly upward to cause the valve 55 toengage with valve seat 58 formed on the lower collar in bore I8. Thelower collar on which valve seat 58 is formed in connection with valve55 forms another chamber 59 in bore 18 in which the valve 55 and itsassociated devices are arranged. The spring 51, as indicated, urges thevalve 55 into engagement with valve seat 58 to thereby govern theopening and closing of the passageway to chamber 68 formed in the upperportion of the bore. A duct 84 is formed in housing I and connects thechamber 59 with chamber 31 for purposes to be hereinafter more fully setforth.

The opening and closing of exhaust valve 52 is determined by pressureconditions existing in chamber H and since the head 48 is arrangedbetween the diaphragms 44 and 45, it is clear that any axial motion ofthe cage 48 with respect to the bore in which it is mounted is under theinfluence of pressure in chamber 4| to thereby govern the opening andclosing of the valve 52 on the disengagement of exhaust valve 52 fromits seat 5|. The valve 55, being under the influence of spring 51,likewise has its operation dependent upon the open or closed position ofthe exhaust valve 52 in order to control the flow of pressure fluidthrough the several .ducts and passageways in the valve. Pressure inchambers 88 and 42 acts on the diaphram 45 when the pressure in 4| islow and urges the diaphragms 44 and 45 upward, thereby assisting inopening the exhaust valve 52. Pressure fluid flows between chambers 42and 58 by leaking 01' bleeding between cage 48 and the housing I becausecage 48 does not snugly fit therein.

,The valve previously discussed is shown organized into atractor-trailer unit schematically illustrated in Figure 3 and istherein designated by the numeral 18. Application valve 13 governs theadmission of pressure fluid to the tractor brake motors 11 and 18 aswell as the admission of pressure fluid to motors 81 and 88 on thetrailer. Each of these motors has cam arms 88, 83, 89, and 88 connectedto their respective motors to apply the motion produced by the motors tothe brakes (not shown) associated therewith.

Pressure fluid derived from pump "is conducted to reservoir 12 byconduit 14 and is conducted therefrom to the inlet side of the manuallyoperated'application valve 13 by means of conduits 15 and 19. Oneapplication port of the valve 13 is connected by means of conduits 8iand 82 to the brake motors 11 and 18 to operate the tractor brakes. Theother application port of valve 13 is connected by means of conduit 84,coupling 85 including appropriate valves, etcetera, and conduit 88 toport 8| of valve 18. Pressure fluid from reservoir 12 is transmitteddirectly to valve 18 by means of conduit 15, coupling 18 includingappropriate valves, etcetera, and conduit 85 to port 4. Conduit 94connects port 5 of valve 18 with trailer reservoir 83 and conduits 9iand 92 connect ports 2 and 3 with the trailer brake motors 87 and 88.Pump II and reservoir I2 are collectively regarded as asource ofpressure fluid supply for the operation of the brake system.

As illustrated in Figures 1 and 2 of the drawings, the device is ininactive position in which there is no air pressure in the severalchambers and with valve I closed. When installed in a tractor-trailercombination, as above set forth, the valve has its port t connected tothe tractor emergency line 95 leading from reservoir l2 and includingconduit I5 and coupling connection it. The trailer reservoir isconnected to port 5 by means of conduit M; the trailer service linecomprising conduit 8%, coupling connection 85, conduit 8 3, etcetera, isconnected to port ti (Figure 2); and the power cylinder lines 9! and92leading to the brake motors Bi and Bii are each connected to ports 2 and1%, respectively.

It will be noted that conduits 9i and 92 originate in chamber Sit invalve Iii; conduit 86 is connected to duct (it which terminates inchamber 3t; conduit 95 terminates at the port d from which pressurefluid can flow into chamber 59 past check valve I which prevents anyreverse flow from chamber 59 back into port and conduit 9 2- originatesin port 5 associated with the chamber 59 Passageways 23, 43, and 6%connect several of the chambers and by a selective or predeterminedpositioning of the valves 26, 3D, 52, and 55 regulate the flow ofpressure value.

fluid from reservoir I2 to reservoir 93, from reservoir 12 to theseveral brake motors, and from reservoir 93 to certain selected brakemotors under predetermined conditions.

Referring now to the operation of the device,

it is assumed that reservoirs I2 and as are empty.

Pump ii is now placed in operation and pressure fluid will exhaust fromit through conduit it into the reservoir I2, the ultimate pressure inthe reservoir being limited by the safety valve Eda. Pressure fluid willflow from reservoir I2 through conduit 1%, coupling I6 andconduit 95into the emergency relay valve Ill through the port 3 and will theredivide, one part going past check Valve I thence into chamber 59 and bymeans of conduit 96 connected to port 5 into the trailer reservoir 93.This how will continue until the pressure in reservoir $3 is nearlyequal to the pressure in reservoir I2, the difference being thatnecessary to actuate check valve 1. The other path of pressure fluidflow is through duct 23, leading from conduit 95 at port t ahead ofcheck valve I into chamber id. The force produced depresses emergencyvalve diaphragm l3 compressing spring 22, and develops sufficientpressure to unseat the valve 25 which remains open as long as pressureis exerted on the emergency Valve diaphragm 93 to overcome spring 22.

The spring 32 closes valve 38 immediately after. the unseating of valve26, thereby preparing the system for operation by application valve I3.If valve I3 is placed in application position, pressure fluid will flowfrom reservoir I2 through conduit I9 to conduit 82 and conduit BI to thetractor brake actuating motors II and I8. Simultaneously pressure fluidwill flow from the application valve I3 through conduit 8 coupling 85and conduit 86 to port 6| of emergency relay valve I0, into chamber 39.It continues to flow through passageways 63 and 62, valve 26 into thechamber 38, thence through duct 43 into the chamber M where it exertspressure on pilot diaphragm M. This causes valve 52 to close andimmediately thereafter opens valve 55. When valve 55 is opened, thepressure fluid in chamber 58, supplied from either reservoir I2 or 93,flows past valve 55, through ports Ed in cage is into chamber and thencethrough ports 3 and 2 respectively connected to conduits 9i and 92 tothe trailer brake motors 81 and 88.

Pressure fluid in chamber 80 will leak or bleed between cage db and themain valve body into chamber 62 and when the force on relay valvedtaphragm 455 becomes equivalent to the oppos ing force on pilotdiaphragm M, valve '55 is closed by spring 5? thereby disconnecting thesource of supply for both relay valve diaphragm 35 and brake motors 8i!and 88, thus maintaining the brakes applied with pressure fluid of agiven If leakage occurs from either the brake motors M and 83 or theconduits connected thereto, a pressure unbalance between chambers M and52 is created which permits pressure fluid in chamber it to again reopenvalve 55 to restore normal operating pressure in said brake motors.

If application valve It is moved to the exhaust position, pressure fluidwill be released from chamber M through duct 63, chamber 38,'valve 26,passageways 62, 63, port ti, conduit 86, coupling 85, conduit 86 andfinally the exhaust port of application valve It to atmosphere. Reactionof the pressure fluid trapped in the braking system between motors ii?and 88 and valve 55 will force diaphragm assembly M and B5 upward andunseat valve 52. The trapped pressure fluid escapes from motors Hand 88by passing through ports 5 of cage 38, valve 52, ducts 5b and vent ll toatmosphere.

Pressure fluid values for the system comprising inlet valve 55 andmotors 8i and 88 will be maintained equivalent to those released byapplication valve I3 to relay valve It by the sequence of operationsjust described.

If a break occurs in coupling it, pressure fluid from chamber Id escapesto atmosphere through duct 23, it being connected to conduit ahead ofcheck valve i, or, if the pressure in reservoir 52 is' abnormally low,the force on emergency valve diaphragm i3 is relieved. When this forcehas been relieved the action of spring 22 forces the emergency valvediaphragm i3 upward, closes valve 2% and immediately thereafter opensvalve 36. This action prevents the escape of any fluid from auxiliaryreservoir 93 through port 68. Pressure fluid from trailer reservoir 93now flows though conduit 9 into port 5, chamber 59, thence through ductM into chamber 3? past valve 3G, through the aperture receiving member2?, into chamber 38 thence through duct t3 into chamber Iii. The actionof this pressure fluid on pilot diaphragm Ml initiates a similar chainof action to that described in the application of pressure fluid to thebrake motors BI and 88 by the actuation of valve I3 to applicationposition. The motors 87 and 88 remain actuated or in a brake appliedposition until normal pressure is restored in reservoir I2 whereupon theemergency valve diaphragm I3 will be depressed to open valve 26,permitting pressure fluid to be exhausted from motors 81 and 88 andreturning the entire system to a normal operating state under thecontrol of application valve I3.

Normally valve I3 is constructed and arranged and trailer units andforms no part or this invention. 1

Under certain conditions it may be desirable to actuate the trailerbrakes without reference to the application valve [3. An auxiliary valveor a two-way valve 981s provided on valve 13 which leads -to one side ofa second manual valve 91 by means of conduit 98. The other side of valve91 is connected to the source of supply in tank I2 by means of conduit99 and a portion of conduit 15. In operation, valve 98 by-passes valve13 to admit pressure fluid to conduit 84 when valve 91 is actuated. Theoperation of emergency relay valve with respect to the trailer brakes isidentical to that described above. Valve 13 is normally foot operatedand valve 91 is normally hand operated. When valve 81 is actuated, thetractor brake motors TI and 18 are not energized. When valve 13 isactuated, all the brake motors will be energized as described above.

It is thus apparent that an emergency relay valve device has beenprovided which is more responsive to disturbances occurring in thepressure fluid supply such as an abnormally low pressure source ofpressure fluid or a failure of the conduits connecting thetractor-trailer device and making certain that the trailer brakes willbe applied in the event that any of the several difliculties occur.

Having fully described my invention, that which I claim as novel anddesire to protect by Letters Patent of the United States is:

l. A brake system comprising a main pressure fluid reservoir; anauxiliary pressure fluid reservoir; fluid-operated brake actuatingmeans; a normally closed inlet valve to control the flow of pressurefluid from said reservoirs to said brake actuating means; a normallyopen exhaust valve to control the exhaust of pressure fluid from saidbrake actuating means; a first diaphragm means to sequentially actuatesaid exhaust and inlet valves; a manually operable valve to control theoperation of said first diaphragm means; a normally closed valveinterposed between said manually operable valve and said flrst mentioneddiaphragm means; a normally open emergency valve interposed between saiddiaphragm means and said auxiliary reservoir; and a second diaphragmmeans to sequentially actuate said normally closed valve and saidemergency valve. said second diaphragm means operated by pressure fluidderived from said main reservoir.

2. A brake system comprising a main pressure fluid reservoir; anauxiliary pressure fluid reservoir; fluid-operated brake actuatingmeans; a

- normally closed inlet valve to' control the flow of pressure fluidfrom said reservoirs to said brake actuating means; a normally openexhaust valve to control the exhaust of pressure fluid from said brakeactuating means; a first diaphragm means to sequentially actuate saidexhaust and inlet valves; a manually operable valve to control theoperation of said first diaphragm means; a normally closed valveinterposed between said manually operablevalve and said first mentioneddiaphragm means; a normally open emergency valve interposed between saiddiaphragm means and said auxiliary reservoir; 2. second diaphragm meansto sequentially actuate said normally closed valve and said emergencyvalve, said-second diaphragm means operated by pressure fluid derivedfrom said main reservoir; and means operative when said second diaphragmmeans is gency valve to open position to establish communication betweensaid auxiliary reservoir and said flrst diaphragm means.

3. A brake system comprising a main pressure fluid reservoir mounted ona tractor; an auxiliary pressure fluid reservoir mounted on a trailer;fluid-operated brake actuating means for. the trailer; a normally closedinlet valve on said trailer to control the flow of pressure fluid fromsaid reservoirs to said brake actuating means; a normally open exhaustvalve on said trailer to control the exhaust of pressure fluid from saidbrake actuating means; a firstv diaphragm means to sequentially actuatesaid inlet and exhaust inoperative to actuate said normally closed valvevalves; a manually operable valve on the tractor to control the flow ofpressure fluid from said main reservoir to said first mentioneddiaphragm means; a normally closed valve on the trailer interposedbetween said manually operable valve and saidfirst mentioned diaphragmmeans; a normally open emergency valve on the trailer interposed betweensaid first diaphragm means and said auxiliary reservoir; and a seconddiaphragm means operable by pressure fluid derived from said mainreservoir to sequentially actuate said normally closed valve to openposition and said emergency valve to closed position to thereby enablesaid manually operable valve to control said first mentioned diaphragmmeans.

4. A brake system comprising a main pressure fluid reservoir; anauxiliary pressure fluid reservoir; fluid-operated brake actuatingmeans; a normally closed inlet valve to control the flow of pressurefluid from said reservoirs to said brake actuating means; a normallyopen exhaust valve to control the exhaust of pressure fluid from saidbrake actuating means; means connecting said exhaust and inlet valves; apilot diaphragm to actuate said inlet and exhaust valves to open andclosed positions, respectively; an application valve to control the flowof pressure fluid from said reservoir to said pilot diaphragm; a relaydiaphragm to actuate said exhaust valve to open position by pressurefluid in said brake actuating means after pressure is relieved from saidpilot diaphragm; a spring to close said inlet valve after said pilotdiaphragm is inoperative thereon; a normally closed valve interposedbetween said application valve and said pilot diaphragm; an emergencyvalve interposed between said auxiliary reservoir and said pilotdiaphragm; means connecting said normally closed valve and saidemergency valve; an emergency valve diaphragm responsive to pressurefluid in said main reservoir to actuate said normally closed valve andsaid emergency valve; and means, when said pilot diaphragm isinoperative, to close said normally closed valve and open said emergencyvalve to establish communication between said auxiliary reservoir andsaid pilot diaphragm to thereby actuate said pilot diaphragm and toenable said brake actuating means to be operated by pressure fluid insaid auxiliary reservoir.

5. A brake system comprising a main pressure fluid reservoir; anauxiliary pressure fluid reservoir; fluid-operated brake actuatingmeans; an emergency relay valve housing; a normally closed inlet valvein said housing to control the flow of pressure fluid from saidreservoirs to said brakeactuating means; a cage movable in a bore insaid housing and having a valve seat therein; a normally open exhaustvalve in said cage engageable with said seat to control the exhaust ofpressure fluid from said brake actuating means; means connecting saidinlet and exhaust 9 valves; a pilot diaphragm to sequentially actuatesaid exhaust valve to closed position and said inlet valve to openposition; a spring to close said inlet valve after said pilot diaphragmis inoperative thereon; a relay diaphragm responsive to pressure fluidin said brake system, the pressure fluid bleeding between said housingand said cage until the pressure on. said relay diaphragm issubstantially equal the pressure'on said pilot diaphragm to therebyenable said spring to close said inlet valve while said exhaust valveremains closed; an application valve to control the flow of pressurefluid from said main reservoir to said pilot diaphragm, said springcontrolling the flow of pressure fluid to said brake actuating meansupon leakage of pressure fluid from said brake actuating means, and saidpres-- sure fluid in said brake system acting on said relay diaphragmupon the exhaust of pressure fluid from said pilot diaphragm to therebyopen said exhaust valve; a normally closed valve in said housinginterposed between said application valve and said pilot diaphragm; anemergency valve interposed between said auxiliary reservoir and saidpilot diaphragm; means connect ing said normally closed valve and saidemergency valve; an emergency valve diaphragm re- ,sponsive to pressurefluid in said main reservoir to sequentially open said normally closedvalve and close said emergency valve; and means operative when saidemergency valve diaphragm is inoperative to reversely operate saidnormally closed valve and said emergency valve to establishcommunication between said auxiliary reservoir and said pilot diaphragmto actuate same so that said brake actuating means may be operatiield bypressure fluid in said auxiliary reser- VO 6. An emergency relay valvecomprising a housing; a normally closed inlet valve in said housto closesaid inlet valve after said pilot diaphragm is inoperative thereon; anormally closed valve in said housing to control the flow oi pressurefluid to said pilot diaphragm; an emergency valve connected to saidnormally closed valve to a control the flow of pressure fluid from anauxiliary pressure fluid supply to said pilot diaphragm; an emergencyvalve diaphragm to sequentially actuate said normally closed valve andsaid emergency valve to open and closed positions; and means toreversely actuate said normally closed valve and said emergency valveafter said emergency valve diaphragm is inoperative.

The following references are or record in the file-of this patent:

UNITED STATES m'rrwrs 2,289,559 Turek July 14,1942

